Device for interconnecting plates between adjacent cells of storage battery

ABSTRACT

A device for interconnecting plates between the adjacent cells of a storage battery is provided which comprises a pair of welding jig members for holding a pair of connector lugs disposed in the adjacent cells respectively and pressing them against a partition wall between the adjacent cell chambers, and an arc welding torch mounted on one of the pair of connector lug holding and pressing members. In operation, the arc is established between the electrode and a projection of one of the pair of connector lugs extended through an aperture of this partition wall and fitted into an aperture of the other connector lug, whereby the pair of connector lugs are fused and joined together.

United States Patent 1191 Inventors: Ichiro Sano, Kanagawa-ken; Sinji vKarasawa, Fujisawa; Tetsuo Sakurai, Odawara-shi, all of Japan MatsushitaElectric Industrial Co., Ltd.," Kadoma-shi, Osaka-fu, Japan Filed: May24, 1972 Appl. No.2 256,333

Assignee:

Int. Cl 823k 9/16 Field of Search 219/127, 125, 75,

References Cited UNITED STATES PATENTS 11/1969 Frindel 219/127 Sano eta1, Nov. 27, 1973 DEVICE FOR INTERCONNECTI-NG PLATES 3,299,249 1/ 1967-Sciaky 219/127 X BETWEEN ADJACENT CELLS 0F 3,437,785 4/1969 Sciaky219/127 X 3,015,022 12/1961 Bowers 219/127 STORAGE BATTERY 3,301,9961/1967 Bidwell 219/127 Primary Examiner-Thomas J. Kozma Attorney-MiltonJ. Wayne et al.

[5 7] ABSTRACT A device for interconnecting plates between the adjacentcells of a storage battery is provided which comprises a pair of weldingjig members for holding a pair of connector lugs disposed in theadjacent cells respectively and pressing them against a partition wallbetween the adjacent cell chambers, and an arc welding torch mounted onone of the pair of connector lug holding and pressing members. Inoperation, the arc is established between the electrode and a projectionof one of the pair of connector lugs extended through an aperture ofthis partition wall and fitted into an aperture of the other connectorlug, whereby the pair of connector lugs are fused and joined together.

8 Claims, 4 Drawing Figures DEVICE?FOR'IIN EER'CONNEC'IING: PLATESBETWEEN. ADJACENT CELLS OF STORAGE BNT'FERY BACKGROUND OF THE INVENTIONThe present inventionrrrelates toa device for interconnectingplates'between the adjacent cells of a storagebatter-y'wi'th apairofconnector lugs one of which has a projection extended through anaperture in a partitioniwall between the adjacent cell chambers-formedintegralwith:a-storage container and fitted into an aperturein the otherconnectorlug.

There has been proposed the intercell connection andmethod ofmaking-same asdisclosed inthe U.S. Pat.'Nos. 3,313,659 andl3,476,61'l inwhich the cellelements inthe adjacent eellsof theso-called monoblocktypeistorage battery having a plurality of partition walls to definethecell cha'mbers are mechanically and electrically connected to'each otherthrough the apertures or openingsin the partition walls. A pair ofconnector lugs'are pressedagainst each other'by a pair of holdingmembersor jaws which also serve as electric conductingmembersso thatthe-current flows throughtheprojections of the pair of connector lugs.to produce the heatito weldthe projections. Therefore, the pair ofconnector'lugs .are welded together with the partition wall interposedtherebetween, but the heating effect upon the-partition wallladverselyaffects the portion-adjacent to the apertureinthepartition wall.Furthermore, there is still-another disadvantage that the heat generatedby the'current passing through the projections is not uniform dependingupon the shapes and especially the contact surface conditions thereof.

SUMMARY OF THE INVENTION According to the present invention, thepressure is exerted to a pair of connector lugs when they are weldedtogether, but unlike the conventional intercell connection method inwhich the resistance'welding is used, the nonconsumable-electrode, inertgas arc welding is used. An electrode is disposed in closely spacedapart relation .withaprojection of one of a pair of connector lugs inthe adjacent cells, respectively, which is extended through an aperturein a partition wall between the adjacentcell cham'bers and fitted intoan aperture in the other connector lug, so that the are between theprojection and the electrode may be concentrated. Therefore, the pair ofprojections may be instantaneously fused and joined together withoutcausing the deterioration of the'portion adjacent to the apertures inthe partition'walls by the thermal and heating effects.

According to one aspect of the present invention, a pair of welding jigmembers for holding a pair of connector lugs and pressing them againstthe partition wall andtoward each other (which will be referred to as apair of pressure membersfor brevity in this specification) and an arcweldingtorch are provided as a unitary construction so that they may beeasily inserted into a narrow cell chamber in a storage battery.Therefore, the pair of connector lugs which may be air-tightly held bythe pair of pressure: members can be welded together in one step.

.BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic sectional viewof a device of the present invention for interconnectingplates betweenthe adjacent cell chambers of a storage battery;

FIG. 2 is a sectional view taken along the line II--II of FIG. 1;

FIG. 3 is a sectional view illustratingthe welded connector lugs betweenthe adjacent cell chambers; and

FIG. 4 is an electric circuit diagram of a welding machine adapted forsequentially welding a plurality of pairs of connector lugs.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

' Referring to FIGS. 1, 2 and 3, a storage battery comprises a containerhaving a plurality of partition walls 1, la and lb formed integral withthe container to define a plurality of cell chambers. In general, theconminer and its partition walls are made of plastic such aspolypropylene, acrylonitrile-styrene (AS),acrylonitrile-butadiene-styrene (ABS) or ebonite. Each of the partitionwalls '1, 1a and 1b has an aperture 2 for passing therethrough aconnector lug. A battery element 3 in which the positive and negativeplates alternate is mounted in each of the cell chambers. A pair ofconducting connector lugs 4 and 4a are formed integral with straps ofthe battery elements 3 and generally made of a lead alloy. When a pairof the conducting lugs 4 and 4a are disposed adjacent to each other withthe partition wall 1 interposed therebetween, one of the conducting lugsfor example 4 is connected to the positive plates whereas the other 4a,to the negative plates.

The conducting lug 4 has an aperture coaxial with the aperture in thepartition wall 1, whereas the other conducting lug 4a has a slightlytapered short projection 6 formed integral with the lug 4a and fittedinto the apertures 2 and5-of. thepartition wall 1 and the lug 4. The

mechanical andelectrical connection between the pair of connector lugs4- and 4a which are spaced apart from each other by the partition wall 1can be made by the following steps.

First the projection 6 of the connector lug 4a is extended through theaperture 2 of the partition wall 1 and fitted into the aperture 5 of thelug 4. In this case, the outer diameter of the projection 6 is soselected as to be slightly smaller than the inner diameters of theapertures 2 and 5 in order to facilitate the fitting, and the length'ofthe projection 6 is so selected as to make the end face of theprojection 6 coplanar with the side surface of the connector lug 4 whichdoes not contact the partition wall 1 or to locate the end of theprojection 6 in the aperture 5 in slightly spaced apart relation fromthe surface of the connector lug 4. Next a pair of welding jig members 7and 7a made of a metal such as steel are inserted into the pair of cellchambers partitioned by the wall 1 so as to press the pair of conductinglugs 4 and 4a against the partition wall 1. According to the presentinvention, one pressure member 7a is pivoted with a pivot pin 8 to theother pressure member 7, and is operatively coupled to a piston 9 of ahydraulic or pneumatic power cylinder 10 so that when the latter isactuated, the pressure member 7a may firmly press the pair of connectorlugs 4 and 4a against the partition wall 1.

The pressure exerted on the pair of connector lugs 4 and 4a in order topress them against the partition wall 1 is determined depending upon thethicknesses of the partition walls and connector lugs which in turn aredependent upon the capacity of storage batteries. For example, pressureof the order from 200 kg/cm to 600 kg/cm is sufficient for pressing theconnector lugs against the partition wall when no air-tight orliquidtight gasket is used. On the other hand when the airtight orliquid-tight gaskets are used between the cell chambers, pressure lessthan 200 kg/cm is sufficient.

Upon the stationary welding jig member 7 is disposed an inert gasdischarge tube generally denoted by 12 comprising a portion A made of anelectrically insulating member such as ceramic 11 having an excellentresistance to heat and an electrically conducting portion B made of ametal member 1 1a such as copper or brass in order to supply the powerto a welding electrode as well be described in more detail hereinafter.An inert gas discharge nozzle 13 which is projecting downwardly from theend of the insulating member 11 is located in an aperture 14 formedthrough the leading end of the stationary welding jig member 7. Atungsten welding electrode 15 is screwed to the conducting portion B andis located along the axis of the nozzle 13. The leading end of thewelding electrode 15 is sharply pointed so that the arc may beconcentrated in operation. An inert gas under pressure such as argon isintroduced into the inert gas discharge tube 12 through a hose 17 and aninlet 16 from an inert gas container (not shown).

One end of an electrode cable 18 is fixed to the conducting portion B ofthe gas discharge tube 12 and the other end is coupled to a plasma spotwelding machine. One end of a grounding cable 19 is fixed to the movablepressure member 7a and the other end is coupled to the plasma weldingmachine. The stationary welding jig member 7 is mounted on a support 20.

Next referring to FIG. 4, the plasma spot welding machine comprisesthree sections. The first section is a power section a which comprises aDC power source 21 with the current capacity of 80 200 amperes; a highfrequency oscillator 22 capable of generating a high frequency of about3 MHz; and a high frequency earthing device 23. The second section is apower supply switching device comprising a timer 24 for controlling atime interval for supplying the current to the welding electrode, and aswitching circuit 25 for sequentially switching the current supplies toa plurality of welding electrodes. The third'section comprises aplurality of torches c each including the welding electrode 15 of thetype described above. In FIG. 4, five torches T T are shown because inthe conventional 12 volt storage batteries, there are six cell chambersdefined by five partition walls, thus requiring five welding operations.In each torch T T the arc is directed from the electrode toward themovable pressure member 7a which presses the connector lug 4a having theprojection 6 against the partition wall 1 and toward the connector lug4.

Referring back to FIGS. 1 and 2, the pair of stationary and movablepressure members 7 and 7a are used to press the pair of connector lugs4a and 4 against the partition wall 1. The power cylinder 10 is actuatedso that the piston 9 moves upwardly to cause the movable welding jigmember 7a to move toward the stationary welding jig member 7. Therefore,the pair of connector lugs 4 and 4a are pressed against the partitionwall 1 between the pair of pressure members 7 and 7a.

Thereafter, the inert gas under controlled pressure and with apredetermined flow rate is introduced into the gas discharge tube orelectrode holder 12 through the inert gas hose l7 and the inlet 16, andis discharged through the nozzle 13 toward the projection 6 of theconnector lug 4a. Next by the plasma spot welding machine the highfrequency, high DC voltage is applied across the electrode 15 and themovable welding jig member 7a so that the arc may be maintained betweenthe electrode 15 and the projection 6 of the connector lug 4a. Since theinert gas issuing from the nozzle 13 cools the arc, the latter is verysharply converged so that a portion of the inert gas is highly ionized.That is, the plasma is created, so that the high temperature rangingfrom 5,000 K to 10,000 K may be maintained. As a result, the peripheryof the aperture 5 of the connector lug 4 and the projection 6 of theconnector lug 4a are instantaneously fused under a high temperature sothat they may be firmly joined together. In this case, the very shortare duration between 0.06 seconds and 0.3 seconds is sufficient toattain the desired joint between the pair of connector lugs 4 and 4a.

Since the movable welding jig member 7a on the side of the connector lug4a having the projection 6 is grounded, the arc may be stabilized. Sincethe argon gas completely covers the welding zone, the oxidization of theconnector lugs in welding operation may be positively prevented.

When the pair of connector lugs 4 and 4a have been joined together, thewelding machine is deactivated to stop the supply of the inert gas, andthereafter the pair of pressure members 7 and 7a are released from thepair of joined connector lugs 4 and 4a and then removed out of thebattery container.

The end portions of the pair of pressure members 7 and 7a are recessedas shown in FIGS. 1 and 2 so that they may easily receive the connectorlugs 4 and 4a when inserted into the storage battery container and pressthem against the partition wall with uniform pressures. Furthermore, theair-tightness of the welding zone may be maintained in operation.

The intercell electrical connections may be accomplished one by one bycycling the above described holding or pressure application step inwhich a pair of connector lugs are pressed against the partition wall bythe pair of welding jig members and welding step, but from thestandpoint of production efficiency it is preferable that all of thepairs of the connector lugs in each battery container are simultaneouslypressed against the partition walls and the supply of the weldingcurrent and/or the inert gas to the welding torches T T (See FIG. 4) isswitched so that the pairs of connector lugs may be sequentially weldedtogether. For this purpose the present invention provides the switchingcircuit 25 (See FIG. 4) so that the supply of the welding current to thetorches may be switched for example in the order of T T T T and T Hencethe efficiency of welding operation may be much enhanced. Furthermore,the are duration may be controlled by the timer 24 for the best resultsdepending upon the thickness of connector lugs.

Next one example of the present invention will be described in which theintercell electrical connections of an automobile storage battery with acontainer and five partition walls formed integral therewith and with anoutput of 12 volts and an ampere-hour capacity of 40 AH were made by thedevice of the present invention.

The battery construction was substantially smilar to that shown in FIGS.1 and 2, and the thickness of the partition walls was 1.5 mm. Theprojection was about mm in diameter and in such a length that its freeend was substantially coplanar with the side surface of the connectorlug when fitted into'the aperture thereof as shown in FIGS. 1 and 2. Apressure of 200 kg/cm was exerted on the pair of connector lugs by thepair of pressure members. The inert gas or argon was discharged throughthe nozzle at a flow rate of 5 l5 l/minute. The DC current of 180 200amperes was used. The pair of connector lugs were firmly joined togetherby the are which lasted only for 0.2 seconds.

In the instant embodiment, the welding jig member 7 has been shown asbeing stationary whereas the pressure member 7a, as being movable, butit should be understood that both welding jig members 7 and 7a may bemovable like a pair of pliers so that they may be moved toward or awayfrom the partition wall.

The diameter of and the spacing between the tungsten electrode and theprojection of the connector lug may be appropriately selected dependingupon the thicknesses of the partition walls and of the connector lugs.

In summary, in the plasma spot welding machine in accordance with thepresent invention, a pair of connector lugs for intercellelectricalconnection between the adjacent battery elements in theadjacent cell chambers of a storage battery are pressed against thepartition wall by a pair of pressure member one of which is movablerelative to the other and held airtightly between the pair of weldingjig members and the partition wall. Thereafter, the arc is establishedbetween the electrode and the projection of one of the pair of connectorlugs so that the latter may be firmly joined together almostinstantaneously. In this case, the arc is completely covered with theinert gas and is very sharply converged or concentrated so that the freeend of the projection of one of the pair of connector lugs may be almostinstantaneously fused and joined to the fused periphery of the apertureof the other connector lug. ln this case, the partition wall interposedbetween the pair of connector lugs will not be adversely affected by thehigh temperature. Hence the thermal and heating effects upon the jointbetween the pair of connector lugs made by the device of the presentinvention is less as compared with the resistance welding in which thepieces of metal are joined by the Jourles heat produced when a largecurrent flows through them.

Furthermore, the presentinvention provides the pair of pressure membersand the torch as a unitary construction so that the device in accordancewith the present invention becomes compact in size and simple inoperation. The pair of pressure members may be easily inserted into thecell chambers even when the width thereof is of the order of 40 mm.

As described above, according to the present invention the intercellelectrical connections for multicell batteries may be accomplished in avery simple yet very efficient manner by the device in which the pair ofpressuree members and the welding torch are provided as a unitaryconstruction compact in-size.

We claim: 1

l. A device for interconnecting plates between adjacent cells of astorage battery wherein a first connector lug has an aperture alignedwith an aperture in a partitioned wall of the battery and a secondconnector lug has a projection extending through the aperture in thewall and into the aperture in the first connector lug; said devicecomprising a welding jig member having first and second jig membershinged together to form first and second pressure members positioned toengage said first and second lugs respectively, means for urging saidpressure members toward each other, and welding torch means in saidfirst pressure member, said torch means comprising an inert gasdischarge tube having an insulating wall portion affixed to said firstpressure member and a conductive wall portion separated from said firstpressure member, a nozzle aperture in said pressure member extendinginto said discharge tube through said insulating wall portion andpositioned for alignment with said projection, and a welding electrodeaffixed to said conductive wall portion and extending axially in saidnozzle aperture.

. 2. The device of claim 1 wherein said gas discharge tube extendslongitudinally along said first pressure member transversely of saidnozzle aperture.

3. The device of claim 1 wherein said welding electrode is removablyscrewed into said conductive wall portion.

4. The device of claim 1 in which said nozzle aperture extendstransversely of said inert gas discharge tube, further comprising aninsulating nozzle extending into said nozzle aperture from saidinsulating wall portion.

5. The device of claim 1 wherein said means for urging said pressuremembers toward, each other comprises-power cylinder means coupled tosaid welding jig member.

6. The device of claim 1 wherein said first pressure member is astationary member, and further comprising inert gas inlet meansconnected to said gas tube, and means connected between said welding jigmember and said conductive wall portion for establishing an are betweensaid welding electrode and projection.

7. The device of claim 1 wherein said first and second pressure membershave recesses to engage said first and second connector lugsrespectively.

8. The device of claim 1 wherein said insulating wall portion is affixedto extend longitudinally in a longitu dinally extending groove in saidfirst pressure member, said conductive wall portion is affixed to saidinsulating wall portion to extend longitudinally therewith, and saidnozzle aperture extends transversely into said tube through saidinsulating wall portion, further comprising a gas inlet extending intosaid gas discharge tube and longitudinally spaced from said nozzleaperture.

1. A device for interconnecting plates between adjacent cells of astorage battery wherein a first connector lug has an aperture alignedwith an aperture in a partitioned wall of the battery and a secondconnector lug has a projection extending through the aperture in thewall and into the aperture in the first connector lug; said devicecomprising a welding jig member having first and second jig membershinged together to form first and second pressure members positioned toengage said first and second lugs respectively, means for urging saidpressure members toward each other, and welding torch means in saidfirst pressure member, said torch means comprising an inert gasdischarge tube having an insulating wall portion affixed to said firstpressure member and a conductive wall portion separated from said firstpressure member, a nozzle aperture in said pressure member extendinginto said discharge tube through said insulating wall portion andpositioned for alignment with said projection, and a welding electrodeaffixed to said conductive wall portion and extending axially in saidnozzle aperture.
 2. The device of claim 1 wherein said gas dischargetube extends longitudinally along said first pressure membertransversely of said nozzle aperture.
 3. The device of claim 1 whereinsaid welding electrode is removably screwed into said conductive wallportion.
 4. The device of claim 1 in which said nozzle aperture extendstransvErsely of said inert gas discharge tube, further comprising aninsulating nozzle extending into said nozzle aperture from saidinsulating wall portion.
 5. The device of claim 1 wherein said means forurging said pressure members toward each other comprises power cylindermeans coupled to said welding jig member.
 6. The device of claim 1wherein said first pressure member is a stationary member, and furthercomprising inert gas inlet means connected to said gas tube, and meansconnected between said welding jig member and said conductive wallportion for establishing an arc between said welding electrode andprojection.
 7. The device of claim 1 wherein said first and secondpressure members have recesses to engage said first and second connectorlugs respectively.
 8. The device of claim 1 wherein said insulating wallportion is affixed to extend longitudinally in a longitudinallyextending groove in said first pressure member, said conductive wallportion is affixed to said insulating wall portion to extendlongitudinally therewith, and said nozzle aperture extends transverselyinto said tube through said insulating wall portion, further comprisinga gas inlet extending into said gas discharge tube and longitudinallyspaced from said nozzle aperture.